LAUSR

Abstract The soot particulates emitted from diesel engines have been ultimately evidenced cancerogenic and successive rigorous emission legislations have been approved in many countries. Monolithic metal-based purification materials are able to tackle the harsh working conditions. Hence, monolithic birnessite MnO 2 /Ni foam catalysts were facilely synthesized via a hydrothermal route and characterized by XRD, Raman spectroscopy, SEM, HRSTEM, XPS, H 2 -TPR, et al. The coating weights are in proportion to hydrothermal temperatures. And the catalyst synthesized at 160 °C displays the lowest T 50 (418 °C) with the coating exfoliation rates of only 0.45 ± 0.11 wt. %. Porous Ni substrates tightly covered with a layer of crosslinked flowerlike birnessite MnO 2 coating would provide many available sites capturing soot particulates. The interphase NiMnO 3 between nanoflowers and Ni substrate could intensify nanoflowers against exfoliation, and inhibit transformation into disordered nanorods. Potassium in the birnessite may activate gas O 2 effectively forming active oxygen species and improve the redox properties. Moreover, nickel dopants inhibit K + thermal evaporation and water dissolution via strengthening K O bonds, thus endowing good reusability. This candidate is likely a promising monolithic catalyst purifying the real diesel exhaust. And the method will be employed to synthesize novel monolithic metallic catalysts for other catalytic applications.